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Research On Open Circuit Pump-Controlled Hydraulic System Of Forging Press

Posted on:2017-03-06Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y SongFull Text:PDF
GTID:1221330503982184Subject:Mechanical and electrical engineering
Abstract/Summary:PDF Full Text Request
Forging industry with huge energy consummation and high pollution emissions into the air in the production has been being the working focus on energy saving and emission reduction, it is the precondition to realize the sustainable development of industry. Compared with the proportional valve-controlled system, the closed circuit pump-controlled system and the direct drive volume control electro-hydraulic servo system, the open circuit pump-controlled forging press system is better to reduce the installed power, the cooling and the fill oil system and to simplify the system structure, and energy saving effect can be improved significantly. At the same time, it retained the advantages of the fast responding, high precision and strong stability of the traditional system. For forging industry, analysis of open circuit pump-controlled volume control characteristics of forging hydraulic press system has important theoretical significance, and the application of the open circuit hydraulic pump-controlled forging press system to the free forging, die forging, multi-ram forging and other equipment has positive practical significance.Forging hydraulic press has the characteristics of time-varying load and random forging process, which requires the hydraulic control system under the condition of different load and forging process having high precision control features. In this paper, the open circuit hydraulic pump-controlled forging press system is taken as the research object where the combination of theoretical analysis and experimental research is adopted, the pressure relief impact inhibition, the separate control of actuator square-cavity and the long pipe system dynamic performance control are researched, based on the characteristics of radial piston variable pump, forging hydraulic press system and forging load. The system control method and response characteristics are analyzed.Firstly, the pressure relief impact of open circuit hydraulic pump-controlled forging press system is researched. The pressure relief rules mathematic models of the energy release laws and the flow release laws are established, and the pressure relief performance in different stages of pressure relief of each curve is analyzed. Based on the different requirerment of the pressure gradient decreased, the combined pressure relief curve is proposed to realize the variable pump eccentric magnitude planning.Secondly, the separate control of actuator square-cavity of open circuit hydraulic pump-controlled forging press system is researched. The separate control of actuator square-cavity mathematic models of the main cylinder position control and the return cylinder pressure control are established, and the coupling effect of the main cylinder system and the return cylinder system is analyzed. Then, the feed-forward load synchronal compensation decoupling control method is proposed. The control precision of the system is improved.Thirdly, the pipe system dynamic performance control of open circuit hydraulic pump-controlled forging press system is investigated. The pipe mathematic model of the hydraulic forging press is established, and the frequently characteristic is analyzed. The feed-forward compensation control based on flow and pressure compound control is proposed. Considering the forging load characteristics, the position control accuracy for the pipe fast forging system with load is improved.Based on 0.6MN hydraulic forging press experimental platform, the experiment can verify the effectiveness of the proposed methods including the pressure relief control by the combined pressure relief curve, the separate control of actuator square-cavity by feed-forward load synchronal compensation decoupling control method and the long pipe system dynamic performance control method by flow and pressure compound control.
Keywords/Search Tags:Forging hydraulic press, Open circuit pump-controlled system, Control of pressure relief impact, Separate control of actuator square-cavity, Decoupling control, pipeline system, Flow pressure compound control
PDF Full Text Request
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